Pour depressants



Patented dot. l0,

PoUR DEPRESSANTS Louis A. Mikeska and Samuel B. Lippincott, Westfield,N. J assignors to Standard Oil Development Company, a corporation ofDelaware N'o Drawing. Application November Serial No. 59,196

v 12 Claims. 1

The present invention relates to improved pour point depressants forlubricating oils and the like. It relates more generally to improvementsin the art of producing wax modifying agents, particularly those whichmay be employed for reducing the pour point of waxy lubricating oils,especially mineral base oils, .or in connection with processes fordewaxing oils containing paraffinic wax. The

invention may have application in other processes or compositions inwhich a wax structure is to be modified by'reducing the crystal size. I

In U. S. Patent 2,251,550, granted to Lieber, there is described aprocess of producing an effective wax modifying agent by heatcondensation-polymerization of the acid chloride which is derived fromfatty acids containing to carbon atoms. The product described in saidpatent has been found highly effective for its purpose, having a pourpoint ceiling of slightly below F. Although this is an excellentshowing, it has been even further improved upon by-the present inventionwhich reduces the pour point of waxy mineral oils to F. byASTM test andat the same time is pour stable to 22 F. by the S. O. D. P our StabilityTest. This test described in detail in Transactions of .American:Society of Automotive Engineers-vol. II, No. 1, pp. 34- 1%. The latterfeature is of considerable importance. 7

According to thepresent invention, satisfactory wax modifying agents-rnaybeprepared by' the direct pyrolysis of mixtures of two or morefatty acid halides. The chlorides are specifically preferred but theother halides, and especially the bromides, are quite useful. For thispurpose, aliphatic. carboxylic acid halides containing from 10 to 30carbon atoms per molecule, the range of 12 to 22 carbon atoms being moregenerally preferred, are heated to a temperature of 400 to 800 F.,preferably 500 to 700 F., for a period of 1 to 10 hours, preferably from2 to 5 hours. While normal atmospheric pressure may be used, reducedpressures are often advantageous in carrying out this process. Theresulting product may be refined in various ways, such as filtration ordistillation, to remove rawmaterials in low boiling condensationproducts or by solvent extraction, clay-treating, and the like.

The exact nature of the chemical processinvolved is not known, but it isbelieved that the process is primarily a dehydrohalogenationcondensationreaction.

The aliphatic acid halides employed, the chlorides for example, in theprocess of the present invention may be straight or branched chaincompounds, saturated or unsaturated, and may be monobasic or polybasic.Preferably at least one monobasic acyl halide is combined with at leastone dibasic acyl halide. Examples of the preferred acids include,stearic acid, palmitic acid, margaric acid, lauric acid,-oleic acid,sebacic aid, coconut oil acids, waxoxidation acids, and the like. Thefollowing description relates mainly to the, chlorides but is applicableto the other halides.

The hydrocarbon base stocks into which the wax modifying agents of thepresent invention are incorporated are preferably waxy mineral baselubricating oils such as a parafiinic lubricating oil base stock or amixed base, which may have beenv subjected to any one or more of thecommonly used refining steps, such as distillation, solvent extraction,acid treating, clay treating, etc., as well as'partial dewaxing. Suchioil base stock may either be one which is within the known lubricatingoil viscosity range or it may be arr-oil of much lowerviscosity, such asa gas oil used in the preparation of hydraulic oils, etc.;

and which may have a viscosity as low as 40 Saybolt seconds at F. Solidor normally solid hydrocarbon bas stocks may be used, such as theparaffin waxes of the type employed for hot melt coating of paper.

In carrying out the invention, it is desirable to use the wax modifyingadditive in proportions of about 0.1 to 5% basedori the weight oflubricating oilbase stock, although usually about 1% issufiicient formost purposes. Proportions of 0.5 to 2% are specifically preferred.- Itwill be understood that different oils require slightly differentamounts of the material to produce a given drop in pour point, andlikewise material prepared fromdiifere'nt types of acids vary some Whatin theirz'pour. depressing strength;

The wax modifying agents of the present in- Vention may be usedinconnection with-the process for 'dewaxing hydrocarbon oils. They maybe added either to the oil to be clewaxed or to the oil after it hasbeen diluted with naphtha or with. other'suitable dewaxing solvents.

be conducted either by filtration, sedimentation or centrifugation lnany case, it will be found that the-presence of a'relatively-sinallamount of the wax modifying material, say 1% more-Ur which, however, isnot to be considered as limiting the scope of the invention in any way.

Example A mixture of one part by weight of sebacyl chloride (20 g.) andnine parts by weight, of stearoyl chloride (180 g.) were heated to 260C. during a period of /2 hour and held at this temperature, :5 C. for 3hours. Considerable quantities of hydrogen chloride were evolved. Thefinal dark waxy product (169 g.) was tested and found to be free ofchlorine. A portion of this material was blended in a base oil of about44 S. U. S. viscosity at 210 F., consisting essentially of a solventextracted Mid-Continent neutral oil plus 3 A conventionally refinedPennsylvania Bright Stock and the pour points of the blends weredetermined.

Pour point of blends, F.

The pour stability of the 1% blend of the pyrolysis product of the mixedacid chlorides, as determined in the S. O. D. Pour Stability Test, asdescribed above, was found to be perfect, i. e., it was still fluid atthe end of the test (-22 F.)

The major portion of the product (150 g.) was extracted three times with1500 cc. portions of acetone. The acetone solutions were combined andconcentrated on the steam bath leaving a rather dark colored wax (100g., Fraction 1). The acetone insoluble portion (50 g., Fraction 2) was ablack tar. The latter contained the active pour depressant as indicatedbelow for blends in the same oil as used above.

A blend of Fraction 2 was subjected to the standard S. O. D. testfor'pour stability. It showed a solid point at -20 F., i. e., it was notquite as good as the crude material in this respect.

The ratio of the dibasic acyl chloride, e. g., sebacyl chloride to themonobasic acyl chloride, such as stearoyl chloride, may be varied. Itmay be as low as 0.05 or may :be increased to 0.5 or higher'withoutimpairing the oil solubility of the product. However, if this ratio isincreased to above 0.8, an oil insoluble product results. The same holdstrue in general for the other acyl chlorides, bromides, and otherhalides.

It is not intended that this invention be limited by any of the exampleswhich have been given merely for the sake of illustration, but only bvthe terms of the appended claims.

What is claimed is:

1. An improved non-volatile waxy hydrocarbon lubrilcating oilcomposition consisting essentially of a waxy mineral oil base stock andfrom 0.1 to 5.0% of a product obtained by heating a mixture of at leasttwo different aliphatic carboxylic acid halides having from 10 to 30carbon atoms per molecule at a temperature of 400 to 800 F. for a periodof 1 to 20 hours.

2. A composition according to claim 1 in which at least one acid halideis a monobasic fatty acid halide and at least one is a dibasic fattyacid halide.

3. Composition according to claim 1 in which said halides are chlorides.

4. Composition according to claim 1 in which said halides are bromides.

5. An improved lubricating composition consisting essentially of a waxymineral lubricating oil base and from 0.1% to 5.0% of a product obtainedby heating a mixture of stearoyl halide and sebacyl halide wherein theratio of the sebacyl halide to the stearyl halide in said mixture isfrom 0.05 to 0.5 at a temperature of 500 to 700 F. for a period of 1 to10 hours.

6. Composition as in claim 5 wherein said halides are chlorides.

7. An improved lubricating oil composition consisting essentially of a.waxy lubricating oil base and from 0.1% to 0.5% of a product obtained byheating a mixture of stearoyl chloride and sebacyl chloride wherein theratio of the sebacyl chloride to the stearyl chloride in said mixture isfrom 0.05 to 0.5 at a temperature of 600 F. for a period of 6 hours.

8. An improved lubricating oil composition consisting essentially of awaxy lubricating oil base and a pour depressing amount of a productobtained by heating together a mixture of about 9 parts by weight ofstearoyl chloride and about 1 part of sebacyl chloride at a temperatureof 600 F. for a period of 6 hours.

9. An improved oil composition consisting essentially of a, waxy mineraloil base of hydraulic oil to lubricating oil viscosity and 0.1 to 5% byweight, based on the weight of the oil, of the product obtained byreacting a monobasic acyl halide with a dibasic acyl halide at atemperat'ure of 400 to 800 F. for a period of 1 to 20 hours.

10. A pour depressant composition for use in waxy oils and the like,consisting essentially of the reaction product of 0.5 to 8 parts byweight of dibasic acyl halide with 10 parts of monobasic acyl halide ata temperature within the range of 400 to 800 F. for 1 to 20 hours.

11. Composition as in claim 10 wherein the halides are chlorides.

l2. Composition as in claim 10 wherein the dibasic acyl halide issebacyl chloride and the monobasic acyl halide is stearoyl halide.

LOUIS A. MIKESKA. SAMUEL B. LIPPINCOIT.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

1. AN IMPROVED NON-VOLATILE WAXY HYDROCARBON LUBRICATING OIL COMPOSITIONCONSISTING ESSENTIALLY OF A WAXY MINERAL OIL BASE STOCK AND FROM 0.1 TO5.0% OF A PRODUCT OBTAINED BY HEATING A MIXTURE OF AT LEAST TWODIFFERENT ALIPHATIC CARBOXYLIC ACID HALIDES HAVING FROM 10 TO 30 CARBONATOMS PER MOLECULE AT A TEMPERATURE OF 400* TO 800*F. FOR A PERIOD OF 1TO 20 HOURS.